The trade association Interpave has added its voice to calls for resisting creation of a possible legal loophole, enabling developers to avoid using sustainable drainage systems (SUDS).

Recent reports that provisions in SUDS National Standards, currently being prepared by the Department for Environment, Food and Rural Affairs (Defra), could include a ‘get-out clause’ are a particular concern. It has been suggested that this might allow developers to use alternative drainage methods where they can demonstrate that SUDS would be disproportionately expensive.  Quite how this is to be demonstrated remains unclear with the continuing delay in publication of the National Standards.

This move flies in the face of the coalition administration’s intent of being "the greenest government ever". It also significantly reduces our ability to defend against a repeat of the widespread flooding events seen in recent years where increased urbanisation and climate change have led to the sewer network being overwhelmed.  The 2010 Flood and Water Management Act, which makes SUDS mandatory, is seen by many as an essential component in the fight against repeats of these flooding events and their cost in both financial terms and human suffering.  

The move could also be seen as unnecessary given the cost-effectiveness of SUDS schemes, particularly those incorporating concrete block permeable paving.  Independent research commissioned by Interpave found that: “concrete block permeable pavements proved the most effective paving solution over 40 years” when using a whole life costing analysis. It also demonstrated that fully infiltrating permeable paving had the lowest initial costs wherever it could be used, when compared with various other impermeable paving materials using concrete block permeable paving with conventional drainage systems.